Cigarette wrapper and cigarette

ABSTRACT

A cigarette has a tobacco section in which cut tobacco is wrapped with a cigarette wrapper, a filter section connected to one end of the tobacco section, and a tip paper integrally connecting the tobacco section to the filter section in a manner to cover the proximal end portion of the tobacco section and the filter section and provided with ventilation holes formed in a circumferential direction in positions apart from the smoking end of the filter section. The tobacco section has a rod length of 30 to 46 mm, and a cut tobacco filling density of 180 to 270 mg/cm 3 . The cigarette wrapper has a basis weight of 17 to 21 g/m 2 , a mixing ratio of a calcium carbonate filler of 16 to 25% by weight, and a calcium carbonate content of 3 g/m 2  or more. The cigarette provides at least six puffs under a standard smoking condition.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a Continuation Application of PCT Application No.PCT/JP00/09194, filed Dec. 25, 2000, which was not published under PCTArticle 21(2) in English.

[0002] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 11-371797, filed Dec. 27,1999, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention relates to a cigarette that permits atleast six puffs in spite of its short rod length of tobacco section.

[0005] 2. Description of the Related Art

[0006] In order to prevent a fire and to suppress sidestream smoke or toprevent carbon dioxide gas generation, a cigarette is proposed having acut tobacco rod with a short length. For example, Japanese Utility ModelNo. 3049857 discloses a cigarette the length of which cut tobacco rod ishalf that of the ordinary cigarette in order to lower the amount ofcarbon dioxide generated per cigarette. Also Jpn. Pat. Appln. KOKAI No.7-327654 discloses a cigarette the length of which cut tobacco rod isdecreased to 1 to 1.5 cm in order to prevent a fire and to suppress thesidestream smoke. It should noted that a cigarette available on themarket provides six to ten puffs under the standard smoking condition(ISO), while such a cigarette having a short cut tobacco rod providespuffs considerably smaller than that provided by the cigarette availableon the market, which fails to satisfy smokers.

[0007] Further, Japanese Patent No. 2834325 discloses a cigarette inwhich a cut tobacco density is set at 300 mg/cc or more in order todecrease a combustion rate of the cut tobacco rod, thereby increasingthe number of puffs provided by the cigarette. It may be possible forthe cigarette of this type to provide a reasonable number of puffs evenif the length of the cut tobacco rod is decreased. However, thecigarette having a cut tobacco density not lower than 300 mg/cc is notadapted for high-speed production. In addition, the cigarette of thistype is substantially equal to the cigarette available on the market inthe amount of ash per puff.

[0008] An object of the present invention is to provide a cigarettewrapper that permits lowering a spontaneous combustion rate, and toprovide a novel cigarette that permits providing the number of puffssatisfactory to smokers in spite of its short length of cut tobacco rod,that is smaller than the conventional cigarette in the amount of ash andsidestream smoke per cigarette and that is economical and harmless tothe earth environment.

BRIEF SUMMARY OF THE INVENTION

[0009] A cigarette wrapper according to the present invention has abasis weight of 17 to 21 g/m², a mixing ratio of a calcium carbonatefiller of 16 to 25% by weight and a calcium carbonate content of 3 g/m²or more.

[0010] According to the present invention, there is provided a cigarettein which cut tobacco is wrapped with the above cigarette wrapper.

[0011] To be more specific, a cigarette of the present inventioncomprises a tobacco section in which cut tobacco is wrapped with acigarette wrapper, a filter section connected to one end of the tobaccosection, and a tip paper integrally connecting the tobacco section tothe filter section in a manner to cover the proximal end portion of thetobacco section and the filter section and provided with ventilationholes formed in a circumferential direction in positions apart from thesmoking end of the filter section; wherein the tobacco section has a rodlength of 30 to 46 mm and a cut tobacco filling density of 180 to 270mg/cm³; and wherein the cigarette wrapper has a basis weight of 17 to 21g/m², a mixing ratio of a calcium carbonate filler of 16 to 25% byweight and a calcium carbonate content of 3 g/m² or more; and whereinthe cigarette provides at least six puffs under the standard smokingcondition.

[0012] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The present inventors have analyzed various factors such ascigarette wrappers, pore sizes of filters and air permeation resistanceof cigarettes in smoking in an attempt to shorten the length of cuttobacco rod. As a result, it has been found that, in the case ofcombining materials used for manufacturing ordinary cigarettes andemploying a standard cut tobacco density, the number of puffs providedby the cigarette is decreased if the length of cut tobacco rod is short,resulting in failure to satisfy smokers. It has been found that, thestandard cut tobacco density brings about a high spontaneous combustionrate of the cigarette, i.e., a combustion rate of the cut tobacco rodunder the state that the cigarette is not smoked, resulting in decreasein the number of puffs. Therefore, it was expected that at least sixpuffs per cigarette, which was satisfactory to smokers, would beachieved, if it would be possible to lower the spontaneous combustionrate of the cigarette.

[0014] The present invention provides a novel cigarette wrapper thatpermits lowering the spontaneous combustion rate of the cigarette, and acigarette prepared by using the particular cigarette wrapper.

[0015] The present inventors have found that, for lowering thespontaneous combustion rate of the cigarette, it is effective to use acigarette wrapper not containing a combustion improver and having asmall basis weight and a small weight ratio of the filler (calciumcarbonate). It should be noted that, in order to roll cut tobacco withthe ordinary cigarette-making machine, it is desirable for the cigarettewrapper to have a tensile breaking load in the vertical direction of 1.0kg/15 mm to 2.0 kg/15 mm. It has been found, however, that, if the basisweight of the cigarette wrapper is excessively small, the tensilebreaking load is rendered smaller than 1.0 kg/15 mm, and that, if thecontent of the filler is excessively decreased, the tensile breakingload of the cigarette wrapper is caused to exceed 2.0 kg/15 mm as wellas a burning cigarette is spontaneously extinguished.

[0016] Based on the findings, the present inventors have developed acigarette wrapper having a basis weight of 17 to 21 g/m², a mixing ratioof a calcium carbonate filler of 16 to 25% by weight and a calciumcarbonate content of 3 g/m² or more.

[0017] The present inventors have also developed a cigarette having arod length of 33 to 46 mm and a cut tobacco filling density of 180 to270 mg/cm³, and providing at least six puffs under the standard smokingcondition, by using a cigarette wrapper having a basis weight of 17 to21 g/m², a mixing ratio of a calcium carbonate filler of 16 to 25% byweight and a calcium carbonate content of 3 g/m² or more. The cigaretteof the present invention has a cut tobacco filling density within astandard range of 180 to 270 mg/cm³ and a shot rod length of 30 to 46mm, more preferably 35 to 42 mm, and yet permits at least six puffsunder the standard smoking condition.

[0018] In the present invention, it is possible to provide cigaretteshaving various tar values matching with tastes for smokers by adjustinga filter section and a tobacco section.

[0019] For example, in the design of a high tar cigarette having a tarvalue in mainstream smoke of 6 mg or more, it is desirable to set theair flowing rate through the ventilation holes (Vf) in the filtersection at 30% or less and to set the mixing ratio of expanded cuttobacco in the cut tobacco at 20% by weight or less.

[0020] The cut tobacco performs a function of lowering the temperatureof smoke. In the cigarette of the present invention, however, the smoketemperature is unlikely lowered because the rod length of the tobaccosection is short. In particular, the smoke temperature is unlikelylowered in the case where the Vf value is low, which possibly impairsthe flavor. However, it is possible to improve the flavor by arranging atip paper connecting the cut tobacco rod to the filter section such thatthe tip paper covers the proximal end portion of the cigarette wrapperover a length of 10 mm or more.

[0021] On the other hand, in the design of a low tar cigarette having atar value in mainstream smoke of 6 mg or less, more desirably 3 mg orless, it is desirable to set the Vf value of the filter section at 50%or more and to set the mixing ratio of expanded cut tobacco in the cuttobacco at 20% by weight or more.

[0022] Also, since the smoke temperature is unlikely lowered in thecigarette of the present invention, if the filter section containsmenthol, the high temperature smoke promotes evaporation of menthol. Itfollows that it is possible to provide a feeling of coolness in smokingmore satisfactorily compared with an ordinary menthol cigarette.

[0023] Examples of the present invention will now be described.

[0024] Cigarettes were prepared by changing in various fashions thedesigns of the tobacco section, the cigarette wrapper and the filtersection, as shown in Table 1. The tobacco section was controlled inrespect of the type of cut tobacco, the rod length, the mixing ratio ofexpanded cut tobacco and the cut tobacco density. The cigarette wrapperwas adjusted in respect of the basis weight, the calcium carbonate(CaCO₃) content, the mixing ratio of the combustion improver, and theair permeability (in CORESTA units). The filter section was adjusted inrespect of the type of filter, the length of the filter and the airflowing rate through the ventilation holes (Vf).

[0025] Table 1 shows three comparison groups, each including threeexamples. In each of comparison groups, a standard article representinga cigarette available on the market or a cigarette close to thecigarette available on the market, a reference article representing acigarette having a cut tobacco rod shorter than that of the standardarticle. Examples 1 to 3 represent cigarettes of the present invention.To be more specific, in the cigarettes of Examples 1 to 3, the cigarettewrapper has a basis weight of 17 to 21 g/m², the mixing ratio of thecalcium carbonate filler of 16 to 25% by weight and the calciumcarbonate content of 3 g/m² or more, and the tobacco section has a rodlength of 30 to 46 mm.

[0026] Table 2 shows the results of measurements of the air permeationresistance, the spontaneous combustion rate, the burned length, thespontaneous combustion time, the tar content in the mainstream smoke,the amount of the sidestream smoke, and the number of puffs in respectof each of the cigarettes that were tested. The combustion state of thecigarette was measured under the standard smoking condition (ISO). TABLE1 Tobacco section Cigarette wrapper Ratio of Cut Ratio of Air TensileFilter section Type of Rod expanded tobacco Basis Ratio of CaCO₃combustion permea- breaking Filter cut length cut tobacco density weightfiller content improver bility load Type of length Vf tobacco mm wt %mg/cm³ g/m² wt % g/m² wt % CU kg/15 mm filter mm % Standard C1 59 0 27022.0 26.8 5.68 1.2 24 1.7 F1 25 20 article Reference C1 40 0 270 22.026.8 5.86 1.2 24 1.7 F1 25 20 article Example 1 C1 40 0 270 20.7 17.93.70 0 7 1.8 F1 25 20 Standard C1 59 0 270 22.0 26.8 5.86 1.2 24 1.7 F225 70 article Reference C1 35 0 270 22.0 26.8 5.86 1.2 24 1.7 F2 25 70article Example 2 C1 35 0 270 20.7 17.9 3.70 0 7 1.8 F2 25 70 StandardC2 59 32 214 28.0 28.0 7.84 0.9 80 1.6 F2 25 72 article Reference C2 4232 214 28.0 28.0 7.84 0.9 80 1.6 F2 25 72 article Example 3 C2 42 32 21420.7 17.9 3.70 0 7 1.8 F2 25 72

[0027] TABLE 2 Air Spontaneous Spontaneous Spontaneous permeationcombustion combustion Burned combustion resistance rate rate length timemmH₂O mm/min mg/min mm min Standard 115  4.72 62.5 49 10.4 articleReference 101  4.72 62.5 30 6.4 article Example 1 113  3.69 48.8 30 8.1Standard 103  4.72 62.5 49 10.4 article Reference 97 4.72 62.5 25 5.3article Example 2 97 3.69 48.8 25 6.8 Standard 97 6.83 71.6 49 7.2article Reference 95 6.83 71.6 32 3.7 article Example 3 95 4.79 50.2 325.2 Amount of Amount of sidestream smoke sidestream smoke Amount of tarper minute per cigarette in mainstream during spontaneous duringspontaneous smoke combustion combustion Number of mg mg/min mg/cigarettepuffs Standard 13.2 2.3 23 8.5 article Reference 9.0 2.3 14 5.2 articleExample 1 10.1 1.7 14 6.2 Standard 3.3 2.3 23 9.9 article Reference 1.92.3 12 5.0 article Example 2 2.4 1.6 11 6.9 Standard 1.3 2.7 19 6.8article Reference 0.9 2.7 10 4.4 article Example 3 1.4 1.6  8 6.0

[0028] As apparent from Table 2, the cigarette for each of Examples 1 to3 exhibited a spontaneous combustion rate lower than that for thecigarette of the reference article, provided at least six puffs in spiteof the shorter rod length of the tobacco section, and was smaller in theamount of the sidestream smoke.

[0029] As described above in detail, the present invention provides acigarette wrapper that permits lowering the spontaneous combustion rate,and provides a novel cigarette that permits the number of puffssatisfactory to smokers in spite of the shorter length of cut tobaccorod as well as permits decreasing the amount of ash and the amount ofsidestream smoke per cigarette, compared with the conventionalcigarette, and is economical and not harmful to the earth environment.

[0030] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A cigarette wrapper having a basis weight of 17to 21 g/m², a mixing ratio of a calcium carbonate filler of 16 to 25% byweight, and a calcium carbonate content of 3 g/m² or more.
 2. Acigarette, wherein cut tobacco is wrapped with the cigarette wrapperaccording to claim
 1. 3. A cigarette, comprising a tobacco section inwhich cut tobacco is wrapped with a cigarette wrapper, a filter sectionconnected to one end of the tobacco section, and a tip paper integrallyconnecting the tobacco section to the filter section in a manner tocover the proximal end portion of the tobacco section and the filtersection and provided with ventilation holes formed in a circumferentialdirection in positions apart from the smoking end of the filter section;wherein the tobacco section has a rod length of 30 to 46 mm and a cuttobacco filling density of 180 to 270 mg/cm³; and wherein the cigarettewrapper has a basis weight of 17 to 21 g/m², a mixing ratio of a calciumcarbonate filler of 16 to 25% by weight, and a calcium carbonate contentof 3 g/m² or more; and wherein the cigarette provides at least six puffsunder a standard smoking condition.
 4. The cigarette according to claim3, wherein the tobacco section has a rod length of 35 to 42 mm.
 5. Thecigarette according to claim 3, wherein a tar content in mainstreamsmoke is not smaller than 6 mg, an air flowing rate through theventilation holes is not higher than 30%, and a mixing ratio of expandedcut tobacco in the cut tobacco is not larger than 20% by weight.
 6. Thecigarette according to claim 3, wherein the tip paper connecting thetobacco section to the filter section covers the proximal end portion ofthe cigarette wrapper in a length not shorter than 10 mm.
 7. Thecigarette according to claim 3, wherein a tar content in the mainstreamsmoke is not larger than 6 mg, an air flowing rate through theventilation holes is not lower than 50%, and a mixing ratio of expandedcut tobacco in the cut tobacco is not smaller than 20% by weight.
 8. Thecigarette according to claim 3, wherein the filter section containsmenthol.